Simultaneous Quantification of Psychotropic Drugs in Human Plasma and Breast Milk and Its Application in Therapeutic Drug Monitoring and Peripartum Treatment Optimization.

BACKGROUND: Therapeutic drug monitoring is recommended for several psychotropic drugs, particularly in sensitive situations such as the peripartum period. This study aimed to develop an ultra-high-performance liquid chromatography-tandem spectrometry method for the simultaneous quantification of 14 psychotropic drugs in human plasma and 4 in breast milk. METHODS: The samples were precipitated with methanol containing the stable isotope-labeled analogs. Chromatographic separation was performed using a Phenomenex Luna Omega Polar C18 column. Detection was performed using a triple-quadrupole mass spectrometer equipped with an electrospray ionization interface. The method was fully validated in plasma according to the European Guidelines on Bioanalytical Method Validation and partially validated in breast milk by determining the intraday precision and accuracy, linearity, lower limit of quantification, and matrix effect. RESULTS: The correlation coefficients of the calibration curves were greater than 0.99. Coefficients of variation ranged from 3.05% to 14.66% and 0.62%-14.90% for internal standard-normalized matrix effect, 1.4%-14.1% and 2.1%-10.4% for intraday precision, and 3.2%-13.9% and 4.1%-9.6% for interday precision, in plasma and milk, respectively. The relative error in accuracy did not exceed ±15% for any analyte. The method was successfully applied clinically to measure the concentrations of psychotropic drugs in 952 plasma samples, among which 43% of the concentrations were out of the therapeutic range, and 13 breast milk samples, with calculated relative infant doses ranging from 0.32% to 8.18%. CONCLUSIONS: To the best of the authors' knowledge, this is the first routine technique validated for the quantification of psychotropic drugs in both plasma and breast milk, allowing for treatment optimization and prevention of adherence issues, including those in breastfeeding patients.

Correlation between assessment of cytochrome P450 1A2 activity and enzyme activity scores, and their relation to clozapine exposure.

AIMS: Cytochrome P450 1A2 (CYP1A2) is involved in the metabolism of antipsychotic drugs such as clozapine and olanzapine. Personalization of these treatments requires an accurate estimation of CYP1A2 activity. In this study, we aimed (1) to evaluate the correlation between activity score (AS), covariate-corrected activity score (CCS) and the phenotype of CYP1A2 using a caffeine test probe and (2) to investigate their relationship with dose-adjusted clozapine concentrations in a subgroup of the cohort. METHODS: A multicentric, retrospective and observational study was carried out in the French university hospitals of Marseille and Tours. CYP1A2 activity was calculated by the paraxanthine/caffeine (17X/137X) ratio determined 4 h after an oral intake of 100 mg caffeine. AS was calculated according to the CYP1A2*1F alleles. CCS was calculated according to the CYP1A2*1F alleles, smoking status and the presence of concomitant inhibitors. RESULTS: As expected, among the 89 patients included, the 17X/137X ratio was significantly higher in patients who smoked. We found a significant but modest correlation between the 17X/137X ratio and CCS (R2 = 0.3, P = 1.74 × 10-8 ) but none between the 17X/137X ratio and AS (R2 = -0.007, P = 0.52). AS was not correlated with dose-adjusted clozapine levels, contrary to CCS (R2 = 0.19, P = 0.016) and especially the 17X/137X ratio (R2 = 0.42, P = 1.7 × 10-5 ). CONCLUSIONS: Correlation with clozapine concentrations showed the advantage of the 17X/137X ratio over the CCS in clozapine dose optimization. CYP1A2 activity, especially when determined by the caffeine probe, may be used to personalize clozapine dosing for patients experiencing treatment failure.

Renal impairment and DPD testing: Watch out for false-positive results!

Measuring uracil (U) levels in plasma is a convenient surrogate to establish dihydropyrimidine dehydrogenase (DPD) status in patients scheduled with 5-fluorouracil (5-FU) or capecitabine. To what extent renal impairment could impact on U levels and thus be a confounding factor is a rising concern. Here, we report the case of a cancer patient with severe renal impairment scheduled for 5-FU-based regimen. Determination of his DPD status was complicated because of his condition and the influence of intermittent haemodialysis when monitoring U levels. The patient was initially identified as markedly DPD-deficient upon U measurement (i.e., U = 40 ng/mL), but further monitoring between and immediately after dialysis showed mild deficiency only (i.e., U = 34 and U = 19 ng/mL, respectively). Despite this discrepancy, a starting dose of 5-FU was cut by 50% upon treatment initiation. Tolerance was good and 5-FU dosing was next shifted to 25% reduction, then further shifted to normal dosing at the 5th course, with still no sign for drug-related toxicities. Further DPYD genotyping showed none of the four allelic variants usually associated with loss of DPD activity. Of note, the excellent tolerance upon standard dosing strongly suggests that this patient was actually not DPD-deficient, despite U values always above normal concentrations. This case report highlights how critical is the information regarding the renal function of patients with cancer when phenotyping DPD using U plasma as a surrogate, and that U accumulation in patients with such condition is likely to yield false-positive results.

Tacrolimus Exposure in Obese Patients: and A Case-Control Study in Kidney Transplantation.

BACKGROUND: Tacrolimus pharmacokinetics in obese (Ob) patients has been poorly studied. In this article, the authors explored the impact of obesity on tacrolimus exposure in kidney transplant recipients (KTRs) and estimated a more suitable initial dosage in this population. METHODS: A retrospective, observational, monocentric case-control study was performed in obese KTRs (BMI > 30 kg/m2) who received tacrolimus between 2013 and 2017 (initial dose: 0.15 mg/kg/d) (actual weight). Nonobese (Nob) controls (BMI <30 kg/m2) were matched for age and sex. Weekly centralized monitoring of tacrolimus trough levels was performed by liquid chromatography/mass spectrometry until the third month (M3). Target trough levels were set between 8 and 10 ng/mL. All patients received antilymphocyte globulin, corticosteroids, and mycophenolate mofetil. RESULTS: Of the 541 KTRs, 28 tacrolimus-treated Ob patients were included and compared with 28 NOb-matched controls. With a mean of 22 assays/patient, tacrolimus trough levels were higher in Ob patients (mean 9.9 versus 8.7 ng/mL; P = 0.008); the weight-related dose of Tac was lower at M3 (mean 0.10 versus 0.13 mg/kg/d, P < 0.0001). The tacrolimus concentration to dose (C0/D) was higher in the Ob cohort [mean 116 versus 76 (ng/mL)/(mg/kg/d); P = 0.001]. In Ob patients, a mean decrease of -4.6 mg/d in the 3 months after tacrolimus initiation was required (versus -1.12 in NOb; P = 0.001) to remain within the therapeutic range. Obesity, high mycophenolate mofetil daily dose at M3, and CYP3A5 expression were independently associated with higher tacrolimus exposure. Four dose-adaptation strategies were simulated and compared with the study results. CONCLUSIONS: An initial dose calculation based on either ideal or lean body weight may allow for faster achievement of tacrolimus trough level targets in Ob KTRs, who are at risk of overexposure when tacrolimus is initiated at 0.15 mg/kg/d. A prospective study is required to validate alternative dose calculation strategies in these patients.

Ledipasvir and tenofovir drug interaction in human immunodeficiency virus-hepatitis C virus coinfected patients: Impact on tenofovir trough concentrations and renal safety.

We evaluate the impact of ledipasvir on both tenofovir plasma trough concentration and estimated glomerular renal function in human immunodeficiency virus-hepatitis C virus coinfected patients receiving a tenofovir-based antiretroviral regimen and treated with ledipasvir/sofosbuvir. Twenty-six patients [81% male, median age: 51 years; hepatitis C virus genotype 1(75%)/4(15%)] were included. Tenofovir trough concentration (interquartile range) increased from 78 ng ml-1 (53-110) at baseline to 141 ng ml-1 (72-176) at 1 month (P = 0.003). No significant difference on estimated glomerular renal function using both Cockroft-Gault and Modification of Diet in Renal Disease formulae, respectively, [median (interquartile range)] was observed between baseline [101.3 ml min-1 (91.1-114.1); 95.6 ml min-1 (86.5-111.2)], 1 month [102.4 ml min-1 (89.8-112.9), P = 0.26; 92.5 ml min-1 (88.1-114.3), P = 0.27], end-of-treatment [96.5 ml min-1 (82.4-115.4), P = 0.39; 95.4 ml min-1 (84.2-105.4), P = 0.16] and 12 weeks after the end of treatment [100.5 ml min-1 (83.3-111.9), P = 0.24; 93.4 ml min-1 (82.2-103.5), P = 0.16]. Three patients progressed from chronic kidney disease stage 1 to stage 2 at 12 weeks post-treatment. A significant increase in tenofovir exposure through P-glycoprotein inhibition by ledipasvir was confirmed without significant impact on glomerular renal function in our population with normal renal function or mild renal impairment.

Pharmacogenetics of anti-cancer drugs: State of the art and implementation - recommendations of the French National Network of Pharmacogenetics.

Individualized treatment is of special importance in oncology because the drugs used for chemotherapy have a very narrow therapeutic index. Pharmacogenetics may contribute substantially to clinical routine for optimizing cancer treatment to limit toxic effects while maintaining efficacy. This review presents the usefulness of pharmacogenetic tests for some key applications: dihydropyrimidine dehydrogenase (DPYD) genotyping for fluoropyrimidine (5-fluorouracil, capecitabine), UDP glucuronosylstransferase (UGT1A1) for irinotecan and thiopurine S-methyltransferase (TPMT) for thiopurine drugs. Depending on the level of evidence, the French National Network of Pharmacogenetics (RNPGx) has issued three levels of recommendations for these pharmacogenetic tests: essential, advisable, and potentially useful. Other applications, for which the level of evidence is still discussed, will be evoked in the final section of this review.

Pharmacogenetics of antidepressant drugs: State of the art and clinical implementation - recommendations from the French National Network of Pharmacogenetics.

Tailoring antidepressant drug therapy to each individual patient is a complex process because these drugs have adverse effects leading to discontinuation. Pharmacogenetics may provide useful information in routine practice for optimizing antidepressant treatment by helping limit toxic effects while maintaining efficacy. This review presents the usefulness of pharmacogenetic tests for P450 cytochromes CYP2C19 and CYP2D6 in psychiatric patients taking antidepressants. Depending on the level of evidence, the French National Network of Pharmacogenetics (RNPGx) has issued recommendations stating that pharmacogenetic tests for CYP2D6 and CYP2C19 genes are potentially useful in psychiatric patients treated with antidepressant drugs.

Effect of fluid loading during hypovolaemic shock on caspofungin pharmacokinetic parameters in pig.

INTRODUCTION: Caspofungin treatment is frequently initiated in shock patients. In the present study, we investigated the influence of hypovolaemic shock requiring fluid loading on the plasma and pulmonary pharmacokinetic parameters of caspofungin in the pig. METHODS: After being anaesthetised and mechanically ventilated, 12 pigs were bled to induce a two-hour deep shock and resuscitated using normal saline based on haemodynamic goals. A one-hour infusion of 70 mg of caspofungin was started at the beginning of the resuscitation period. The lungs were removed four hours after caspofungin administration. Sixteen animals served as controls without haemorrhage. Caspofungin concentrations were measured by using high-performance liquid chromatography, and a two-compartment population pharmacokinetic analysis was performed. RESULTS: In the shock group, the volume of blood removed was 39 ± 7 mL/kg and a volume of 90 ± 17 mL/kg saline was infused throughout the resuscitation period. The extravascular lung water index was higher in the shock group (9.3 ± 1.6 mL/kg vs 5.7 ± 1 mL/kg in the control group; P < 0.01). In the shock group, the median (interquartile range) maximal plasma concentration was 37% lower than in the control group (21.6 µg/mL (20.7 to 22.3) vs 33.1 µg/mL (28.1 to 38.3); P < 0.01). The median area under curve (AUC) from zero to four hours was 25% lower in the shock group than in the control group (60.3 hours × µg/mL (58.4 to 66.4) vs 80.8 hours × µg/mL (78.3 to 96.9); P < 0.01), as was the median lung caspofungin concentration (1.22 µg/g (0.89 to 1.46) vs 1.64 µg/g (1.22 to 2.01); P < 0.01). However, the plasma-to-tissue ratios were not different between the groups, indicating that lung diffusion of caspofungin was not affected after shock followed by fluid loading. Pharmacokinetic analysis showed that the peripheral volume of distribution of caspofungin and intercompartmental clearance were significantly higher in the shock group, as was the total apparent volume of distribution. CONCLUSIONS: Hypovolaemic shock followed by fluid loading in the pig results in a significant increase in the apparent volume of distribution of caspofungin and in a decrease in its plasma and pulmonary exposition. Although our model was associated with capillary leakage and pulmonary oedema, our results should be generalised to the septic shock with caution. Future investigations should focus on monitoring plasma caspofungin concentrations and optimal caspofungin dosing in shock patients.

[Evidence-based therapeutic drug monitoring for nevirapine]. / Niveau de preuve du suivi therapeutique pharmacologique de la névirapine.

Nevirapine, a HIV non nucleosidic reverse transcriptase inhibitor, displays an inter-individual variability in its pharmacokinetics parameters, related to its hepatic metabolism. Based on literature, is the nevirapine therapeutic drug monitoring relevant? In naïve and pre-treated HIV infected patients, the probability of achieving and maintaining an undetectable HIV viral load was significantly associated with a nevirapine plasma trough concentration (C(trough)) > 4 000 ng/mL. The probability of virologic failure was significantly associated with a C(trough) < 3 000 ng/mL. Concerning the exposure-toxicity relationship, the emergence of hepatotoxicity was more frequently associated with high C(trough), especially in case of HCV coinfection. Non-randomized studies have reported the interest of nevirapine therapeutic drug monitoring to optimize the virologic response and, to a lesser extent, to prevent hepatotoxicity. Therefore, the level of evidence of the interest of nevirapine therapeutic drug monitoring is "recommended".

[Not Available]. / Niveau de preuve du suivi therapeutique pharmacologique de la névirapine.

Nevirapine, a HIV non nucleosidic reverse transcriptase inhibitor, displays an inter-individual variability in its pharmacokinetics parameters, related to its hepatic metabolism. Based on literature, is the nevirapine therapeutic drug monitoring relevant? In naïve and pre-treated HIV infected patients, the probability of achieving and maintaining an undetectable HIV viral load was significantly associated with a nevirapine plasma trough concentration (Ctrough) >4000 ng/mL. The probability of virologic failure was significantly associated with a Ctrough <3000 ng/mL. Concerning the exposure-toxicity relationship, the emergence of hepatotoxicity was more frequently associated with high Ctrough, especially in case of HCV coinfection. Non-randomized studies have reported the interest of nevirapine therapeutic drug monitoring to optimize the virologic response and, to a lesser extent, to prevent hepatotoxicity. Therefore, the level of evidence of the interest of nevirapine therapeutic drug monitoring is "recommended".

[Evidence-based therapeutic drug monitoring for ribavirine]. / Niveau de preuve du suivi therapeutique pharmacologique de la ribavirine.

Ribavirin in combination with pegylated interferon alpha is the current treatment for chronic hepatitis C (HCV). Ribavirin presents a wide inter-individual pharmacokinetic variability and adequate exposure seems crucial for achieving sustained virologic response. Severe anaemia frequently occurred under ribavirin treatment and is a dose-dependent limiting side effect. Several studies have been carried out in HVC-infected or HIV-HCV co-infected patients to evaluate the pharmacokinetic-pharmacodynamic relationships of ribavirin. Achievement of a sustained virologic response, defined as undetectable HCV-RNA six months after the end of treatment, have been significantly associated with ribavirin concentration. A cut-off for the trough concentration of ribavirin ranging between 2-3 µg/ml at week 4 has been proposed. A significant correlation has also been reported between ribavirin concentration and the extent of haemoglobin decline. A ribavirin concentration >2 µg/ml is significantly associated to an increase risk of severe anaemia. Non randomized studies have shown that therapeutic drug monitoring of ribavirin improve the management of therapeutic response and haematologic toxicity. Therefore, the level of evidence of the therapeutic drug monitoring of ribavirin is recommended.

[Not Available]. / Niveau de preuve du suivi therapeutique pharmacologique de la ribavirine.

Ribavirin in combination with pegylated interferon alpha is the current treatment for chronic hepatitis C (HCV). Ribavirin presents a wide inter-individual pharmacokinetic variability and adequate exposure seems crucial for achieving sustained virologic response. Severe anaemia frequently occurred under ribavirin treatment and is a dose-dependent limiting side effect. Several studies have been carried out in HVC-infected or HIV-HCV co-infected patients to evaluate the pharmacokinetic-pharmacodynamic relationships of ribavirin. Achievement of a sustained virologic response, defined as undetectable HCV-RNA six months after the end of treatment, have been significantly associated with ribavirin concentration. A cut-off for the trough concentration of ribavirin ranging between 2-3µg/ml at week 4 has been proposed. A significant correlation has also been reported between ribavirin concentration and the extent of haemoglobin decline. A ribavirin concentration>2µg/ml is significantly associated to an increase risk of severe anaemia. Non randomized studies have shown that therapeutic drug monitoring of ribavirin improve the management of therapeutic response and haematologic toxicity. Therefore, the level of evidence of the therapeutic drug monitoring of ribavirin is recommended.

[Pharmacogenetics for patient care in France: A discipline that evolves!] / La pharmacogénétique au service du soin en France : une discipline qui évolue !

Pharmacogenetics, which concepts are known for a long time, is entering a new period at least as far as its practical applications for patients are concerned. In recent years there have been more and more initiatives to promote widespread dissemination, and health authorities are increasingly incorporating these concepts into drug labels. In France, the national network of pharmacogenetics (RNPGx) works to promote these activities, both with health actors (biologists, clinicians) and health authorities. This article reviews the current situation in France and the milestones of the year 2018. It highlights recent advances in this field, in terms of currently recommended analyses, sharing of information or technological developments, and the prospects for future developments in the near future from targeted pharmacogenetics to eventually preemptive approaches.

A Simple and Rapid UPLC-UV Method for Detecting DPD Deficiency in Patients With Cancer.

Detecting patients with dihydropyrimidine dehydrogenase (DPD) deficiency is becoming a major concern in clinical oncology. Monitoring physiologic plasma uracil and/or plasma uracil-to-dihydrouracil metabolic ratio is a common surrogate frequently used to determine DPD phenotype without direct measurement of the enzymatic activity. With respect to the increasing number of patients rquiring analysis, it is critical to develop simple, rapid, and affordable methods suitable for routine screening. We have developed and validated a simple and robust ultraperformance liquid chromatography-ultraviolet (UPLC-UV) method with shortened (i.e., 12 minutes) analytical run-times, compatible with the requirements of large-scale upfront screening. The method enables detection of uracil (U) over a range of 5-500 ng/ml (265 nm) and of dihydrouracil (UH2) over a range of 40-500 ng/ml (210 nm) in plasma with no chromatographic interference. When used as part of routine screening for DPD deficiency, this method was fully able to discriminate nondeficient patients (i.e., with U levels < 16 ng/ml) from deficient patients at risk of severe toxicity (i.e., U > 16 ng/ml). Results from 1 month of routine testing are presented and, although no complete deficits were detected, 10.7% of the screened patients presented DPD deficiency and would thus require s decresed dose. Overall, this new method, using a simple preanalytical solid-phase extraction procedure, and based on use of a standard UPLC apparatus, is both cost- and time-effective and can be easily implemented in any laboratory aiming to begin routine DPD testing.

Validation of an electrospray ionization LC-MS/MS method for quantitative analysis of raltegravir, etravirine, and 9 other antiretroviral agents in human plasma samples.

BACKGROUND: Raltegravir is the first human immunodeficiency virus-1 (HIV-1) integrase inhibitor used in treatment-experienced patients who have evidence of viral replication and HIV-1 strains resistance to multiple antiretroviral regimens. Etravirine is a novel NNRTI, active against HIV-1 strains harboring multiple NNRTI mutations. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the quantification of raltegravir, etravirine, and 9 other antiretroviral agents (amprenavir, atazanavir, darunavir, efavirenz, indinavir, lopinavir, ritonavir, saquinavir, and tipranavir) in plasma at the concentrations associated with therapy. MATERIALS AND METHODS: The ritonavir analog, methyl indinavir, and lopinavir-d8 were used as internal standards, added to 100 microL of plasma sample prior to a protein precipitation using methanol. Chromatographic separation was achieved on a C18 HPLC column (Waters Sunfire 100 x 2.1 mm, 3.5 microm) with a mobile phase gradient at a flow rate of 0.3 mL/min. Five microL of sample were injected into the LC-MS/MS system (Waters Quattro Premier XE) to determine concentrations of raltegravir, etravirine, and other antiretroviral agents. RESULTS AND DISCUSSION: This method showed an excellent linearity for all calibration curves (r2 > 0.998). The lower limit of quantification was established at 5 ng/mL for raltegravir and 40 ng/mL for etravirine, with precision and accuracy within +/-20% and 80% to 120% for all analytes. Intraassay and interassay precision and inaccuracy ranged from -9.2% to 6.9% for raltegravir and from -14.3% to 12.3% for etravirine and were less than 15% for all other compounds. No matrix effect was observed for any of the antiretrovirals studied. CONCLUSION: A rapid, specific, and sensitive LC-MS/MS method for quantification of raltegravir, etravirine, and 9 other antiretrovirals in human plasma was developed and was successfully applied for routine therapeutic drug monitoring.

Lethal toxicities after capecitabine intake in a previously 5-FU-treated patient: why dose matters with dihydropryimidine dehydrogenase deficiency.

Dihydropryimidine dehydrogenase (DPD) deficiency is a pharmacogenetic syndrome associated with severe or lethal toxicities with oral capecitabine. Usually, patients with history of 5-FU-based therapy with no signs for life-threatening toxicities are considered as not DPD-deficient individuals who can be safely treated next with capecitabine if required. Here we describe the case of a woman originally treated with standard FEC100 protocol for metastatic breast cancer with little severe toxicities but grade-3 mucosities that were quickly resolved by symptomatic treatment. When switched to capecitabine + vinorelbine combo, extremely severe toxicities with fatal outcome were unexpectedly observed. Pharmacogenetic investigations were performed on cytidine deaminase and DPYD, and showed that this patient was heterozygous for the 2846A>T mutation on the DPYD gene. DPD phenotyping (i.e., uracil plasma levels >250 ng/ml, dihydrouracil/uracil ratio <0.5) confirmed that this patient was profoundly DPD deficient. Differences in fluoropyrimidine dosing between FEC100 (i.e., 500 mg/m2 5-FU) and capecitabine (i.e., 2250 mg daily) could explain why initial 5-FU-based protocol did not lead to life-threatening toxicities, whereas capecitabine rapidly triggered toxic death. Overall, this case report suggests that any toxicity, even when not life threatening, should be considered as a warning signal for possible underlying profound DPD deficiency syndrome, especially with low-dose protocols.

[Dihydropyrimidine déhydrogenase (DPD) deficiency screening and securing of fluoropyrimidine-based chemotherapies: Update and recommendations of the French GPCO-Unicancer and RNPGx networks]. / Dépistage du déficit en dihydropyrimidine déshydrogénase (DPD) et sécurisation des chimiothérapies à base de fluoropyrimidines : mise au point et recommandations nationales du GPCO-Unicancer et du RNPGx.

Fluoropyrimidines (FU) are still the most prescribed anticancer drugs for the treatment of solid cancers. However, fluoropyrimidines cause severe toxicities in 10 to 40% of patients and toxic deaths in 0.2 to 0.8% of patients, resulting in a real public health problem. The main origin of FU-related toxicities is a deficiency of dihydropyrimidine dehydrogenase (DPD), the rate-limiting enzyme of 5-FU catabolism. DPD deficiency may be identified through pharmacogenetics testing including phenotyping (direct or indirect measurement of enzyme activity) or genotyping (detection of inactivating polymorphisms on the DPYD gene). Approximately 3 to 15% of patients exhibit a partial deficiency and 0.1 to 0.5% a complete DPD deficiency. Currently, there is no regulatory obligation for DPD deficiency screening in patients scheduled to receive a fluoropyrimidine-based chemotherapy. Based on the levels of evidence from the literature data and considering current French practices, the Group of Clinical Pharmacology in Oncology (GPCO)-UNICANCER and the French Network of Pharmacogenetics (RNPGx) recommend the following: (1) to screen DPD deficiency before initiating any chemotherapy containing 5-FU or capecitabine; (2) to perform DPD phenotyping by measuring plasma uracil (U) concentrations (possibly associated with dihydrouracil/U ratio), and DPYD genotyping (variants *2A, *13, p.D949V, HapB3); (3) to reduce the initial FU dose (first cycle) according to DPD status, if needed, and further, to consider increasing the dose at subsequent cycles according to treatment tolerance. In France, 17 public laboratories currently undertake routine screening of DPD deficiency.

ITPA deficiency and ribavirin level are still predictive of anaemia in HCV-HIV-coinfected patients receiving ribavirin combined with a first-generation DAA (ANRS HC27 study).

BACKGROUND: We aimed to determine the impact of inosine triphosphatase (ITPA) deficiency on ribavirin (RBV)-induced anaemia in HIV-HCV-coinfected patients receiving a triple therapy including the haematotoxic direct-acting antiviral agent boceprevir (BOC). METHODS: Patients of the ANRS HC27 BocepreVIH study were genotyped for two ITPA single nucleotide polymorphisms involved in ITPA deficiency. RBV trough concentration (Ctrough) was determined at week (W)4 and W8. Impact of ITPA deficiency on anaemia, RBV Ctrough, response and haematotoxicity (grade 3/4 anaemia, erythropoietin [EPO] use, RBV dose reduction or transfusion between day [D]0 and W8) was evaluated. Impact of RBV Ctrough on anaemia was also studied. RESULTS: Among the 63 genotyped patients, 33% had a predicted ITPA deficiency. ITPA deficiency was associated with a lower haemoglobin (Hb) decline both at W4 (-1.0 g/dl versus -2.1 g/dl; P=0.02) and W8 (-2.7 g/dl versus -4.1 g/dl; P=0.05). None of the patients with ITPA deficiency received EPO between D0-W8 versus 26% of patients without ITPA deficiency (P=0.01). RBV Ctrough was associated with Hb decrease both at W4 and W8 and an RBV Ctrough cutoff value of 2 µg/ml was significantly associated with a W4 Hb decline >2 g/dl. Haematotoxicity was significantly associated with a lower W4 Hb level (P=0.017), absence of ITPA deficiency (P=0.018) and higher RBV Ctrough (P=0.012). ITPA deficiency, W4 RBV Ctrough and gender were independent predictors of anaemia at W4. ITPA deficiency was not associated with virological response. CONCLUSIONS: ITPA deficiency and RBV Ctrough are still predictive of RBV-induced anaemia in HIV-HCV-coinfected patients treated with RBV combined with a first-generation direct antiviral agent.

Identification by single-strand conformational polymorphism analysis of known and new mutations of the CYP3A5 gene in a French population.

The cytochrome P450 3A5 (CYP3A5) has been shown to be highly involved in the metabolism of many therapeutic agents. To date, several polymorphisms affecting the CYP3A5 gene have been identified but few studies have shown a complete description of the variability of the CYP3A5 in the French population. Therefore, the extent of CYP3A5 genetic polymorphism was investigated in a French population of 114 patients. The screening of the coding region with their intron-exon boundaries and the proximal flanking regions was performed using a PCR-SSCP strategy. Eighteen polymorphisms were identified, including four new mutations. They correspond to -19 T>C upstream of the exon 1, 7360 T>C in intron 4, 12991 T>C in intron 5 and 29788 delG in exon 12. We also identified 13 alleles including six new alleles. As expected, the most frequent allelic variant is CYP3A5*3, with a frequency of 87% of all alleles. These data confirmed that CYP3A5 gene is highly polymorphic. Furthermore, it will be now interesting to evaluate the impact of this polymorphism on the pharmacokinetic parameters of different drugs.